Figure 3.

Narrow band spectrograms. (a) a bout of common roars, showing a clearly defined harmonic structure and modulated formants. The formants drop as the stag extends its vocal tract (by lowering its larynx) and reach a minimum plateau corresponding to the fully extended vocal tract. (b) A harsh roar, showing a noisy glottal wave (deterministic chaos) and well-defined, non-modulated formant frequencies. Formants are at their lowest throughout as harsh roars are given with a maximally extended vocal tract. (c) Detailed structure of a common roar that includes nonlinear phenomena: subharmonics and deterministic chaos; both features confer a harsh quality to roars (adapted from Reby & McComb 2003b).